Studies of a unique new type of polyoma virus variant recently described in the laboratory are proposed to define the mechanism by which the rate of synthesis of capsid polypeptide in this variant is significantly enhanced. The role of virus specific RNA transcription, the processing of viral messenger RNA and the translation of capsid polypeptide specific messenger RNA will be studied. A hamster tumor cell line transformed by this variant has been found to have a markedly diminished rate of processing of small, newly replicated DNA fragments to form high MW DNA. Experiments to define the mechanism of the altered rate of processing of this DNA are proposed and the role of the variant virus in the etiology of the abnormality will be studied. These studies are designed to provide information on the mechanism by which the genetic information of a small oncogenic DNA virus is regulated in a permissive host cell and how certain vital host cell functions, such as DNA synthesis, are modulated by that virus during the process of oncogenesis.